Lady Diana Spencer: Diana was born Diana Frances Spencer to John Spencer, Viscount Althorp and the 8th Lord Spencer, and Frances Roche. She was 7 years old when her parents divorced, and when her father inherited the title of Lord Spencer in 1975, she became known as Lady Diana Spencer. Her father moved the family to Althorp, the Spencer estate in Northampton, England. It was this title that earned Diana the nickname "Lady Di."

Her Royal Highness the Princess of Wales: During her marriage to Prince Charles, Diana held the HRH and was officially known as the Princess of Wales. Throughout this time, she also held the title of Duchess of Cornwall, which now belongs to Charles's current wife, Camilla.

Diana, Princess of Wales: After her divorce from Prince Charles was finalised in August 1996, Queen Elizabeth II reportedly wanted to let Diana keep the style of her royal highness, but Charles was "adamant" that she give it up — instead, she was given the title Diana, Princess of Wales. The loss of the honourific separated Diana from the rest of the family in such a way that she had to curtsy to those who had it, including her own children. Prince William, then 14, is said to have comforted his mother after the loss of her title by saying, "Don't worry, Mummy, I will give it back to you one day when I am king." At the time of her death and to this day, she is officially known as Diana, Princess of Wales.